Second marriage and barons' revolt
In 1228, probably after June, Elizabeth married John, a younger son of the House of Béthune who had followed a military career and possessed neither land nor money. His brother Daniel, lord of Béthune, was the first husband of Elizabeth's daughter. Shortly after her second marriage, Elizabeth wrote to the abbot of Anchin, from whom she held a small fief, asking him to receive homage from John "whom I legally married". The marriage does not have the appearance of a love match and, with Elizabeth beyond childbearing, was probably part of larger web of alliances.
The marriage took place during a rebellion against Blanche of Castile, widow of Louis VIII and regent for her son, Louis IX. It was likely arranged by Ferdinand, Count of Flanders, one of Blanche's supporters and John of Béthune's former employer, in order to shore up his southern flank against Count Philip I of Boulogne. In December 1226, Blanche had transferred the homage owed by Saint-Pol to the crown—which had been acquired in 1211 when Philip II confiscated the county of Boulogne from Renaud of Dammartin—back to Boulogne, but the count had turned against her.
Hugh, who followed his new suzerain against Blanche, opposed his mother's second marriage and sought to have it annulled. He charged his ally, Enguerrand III of Coucy, to bring the case before the bishop of Tournai and the archbishop of Reims in November 1228 as a third party. Although the marriage was within prohibited degree of kinship, Hugh's efforts failed to overturn it. In December, however, he began styling himself Count of Saint-Pol, dropping the more technically correct form "son of the count" that he had been using.
As part of his alliance with Elizabeth, Ferdinand gave her an annuity of 40 pounds of Artois from the revenue of the fair of Torhout, which she gave to the abbey of Cîteaux in July 1231. In 1229, Ferdinand ravaged the county of Saint-Pol "as far as the castle of Frévent", Elizabeth's residence, according to the chronicler William of Andres, who adds that his goal was to "disinherit" Hugh of Châtillon. The chronicler does not say that he intended to restore Elizabeth to her full powers, although it would have been the natural outcome. The broader purpose of his campaign was to relieve the pressure on his ally, Count Theobald IV of Champagne. He was defeated, and in September 1230 Blanche ordered the raids to cease. By the end of the year the warring factions had made peace, recognizing Louis IX as king with Blanche as regent. Hugh was in control of the county and Elizabeth was restricted to Frévent and Encre.